How to add/remove CSS inline-style with the DOM

Set

To set an inline style, you use:

• the qualified method: element.style.setProperty method of an element

element.style.setProperty(property, value, priority);

// example
element.style.setProperty('color', 'purple', 'important')

• or the shortcut that will set the attribute to a low priority

button.style.color = "purple";

Demo:

• The button that when clicked will change its text color

<button style="color: blue">Click to change my color</button>

• We select the first button, add event listener that execute a callback function using the target element (ie the button) to change the style

document.querySelector('button').addEventListener("click", function(event) { 
    button  = event.target;
    color = button.style.color;
    if(color=="blue"){
       // qualified  method
        button.style.setProperty('color',"purple","important");
    } else {
        // property set method
        button.style.color = "blue";
    }
});

• Click on the button to see it in action

Get

• The property value or an empty string if not set

value = el.style.getPropertyValue('cssProperty');

• The priority value or an empty string if not set

priority = el.style.getPropertyPriority('cssProperty');